Fabrication of protein gradients for cell culture using a miniature squeegee.

We present a straightforward method to create spatial gradients of substrate bound protein for live cell studies using only mechanical parts. Protein concentration gradients on a micron scale can be fabricated in several minutes for a relatively low cost using a method that is generally applicable to any protein and substrate combination. We describe the details of the device construction, and provide examples of mammalian cells grown on substrates patterned with protein concentration gradients using this technique.